Hi,
Does anyone know the dioptric(?) power of the Canon 500D closeup lens. I am planning to buy +3 & +2 diopters for my 12-24 and hopefully-soon-to-be-mine 17-55 in an 8" aquatica dome. I have the 500D as a closeup lens for my 80-400mm topside but I cannot find its power listed as +1,+2,+3 etc anywhere including Canon's website . Its an excellent (and expensive) closeup lens and I was wondering if it would work in place of other diopters?

Cheers,
Chris

Hey Chris -

I believe the 500D is a +2 diopter.

I posted this else where a few days ago. The Canon naming convention for the diopters is very sensible. The part number is the maximum focus distance in millimeters: 500D = 1/2 meter = +2 , 250D = 1/4 meter = +4 ,...

Herb, that is only sensible for the rest of the world... you are the only american who understands metric...

And the reason that 500mm is the maximum focus distance is because the focal length of the 500D is 500mm (250D is 250mm), even more sensible to me. This makes 500mm the maximum focus distance because an object at the focal length of a lens is focused at infinity. So as far as your camera is concerned, an object at the focal distance of your diopter appears to be at infinity.

Bart

Thanx for the help guys. I never realized that a +1 diopter meant 1 meter max focus, +2 meant 1/2 meter max focus etc.. makes sense

Cheers,
Chris